Systems of Equations: The Basics

A system is two equations that are true at the same time. They share the same $x$ and the same $y$. The solution is the one pair of numbers that makes both equations true, and it is written as a point, $(x, y)$.

There are two methods you need. The first is substitution. Use it when one equation already tells you what a variable equals, like $y = 4$ or . Put that value into the other equation in place of the variable, then solve for the letter that is left.